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NEMA rating for Enclosures

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    NEMA rating for Enclosures

    What NEMA enclosure rating do I need for a Class 1 Division 1 or 2 areas? I’m just splicing some wire together. No equipment in the enclosures.

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    The basic enclosure rules are in Sections 501.10 (A)(3) and 501.10(B)(4).

    For splices only, Division 1 enclosures must still be approved for Division 1. Explosionproof is the most common, Other protection technique options may be found in Section 500.7. Be careful to observe Section 501.15(A)(1)(2) as well.

    Again for splices only, virtually any enclosure that would otherwise be acceptable in the environment would be suitable.

    FYI, the "General Purpose" enclosure "Types" are listed in Section and Table 110.28. While it is still common practice, they are no longer properly called NEMA types.
    Robert B. Alexander, P.E.
    Answers based on 2017 NEC unless otherwise noted.


      But to specifically answer your question, NEMA type 7 is (was) for Class I, Division 1, Groups A, B, C, or D. You can use a NEMA 7 enclosure for Class 1 Division 2 if you like, but often for Division 2 areas you can use regular enclosures with devices inside that are rated for use in Div. 2 environments.

      As Bob says though, NEMA types are not official, they are guidelines. OFFICIALLY, the enclosure must be rated, typically by an NRTL such as UL, for the environment it will be used in. UL enclosure types generally match the old NEMA standards (i.e. UL Type 1, 3R, 4, 12 etc.), but UL stops using those designation numbers for classified environments. So for Explosion Proof enclosures, there is no UL Type 7, UL gets specific about Class, Division and Group. But you will see that the explosion proof enclosure mfrs will still market them as NEMA type 7, you just need to ensure what division and group they are listed for.
      __________________________________________________ ____________________________
      Many people are shocked when they discover I am not a good electrician...

      I'm in California, ergo I am still stuck on the 2014 NEC... We'll get around to the 2017 code in around 2021.